It is desirous in a single reel tape cartridge to provide a means for interconnecting the tape web into the tape driving system in a manner that does not require operator intervention together with a positive and easily connected interconnection. An automatic threading apparatus generally includes a coupling device and a mechanism for moving the coupling device over a predetermined non-linear path extending from the supply reel within the cartridge to a take-up reel in the tape transport device. The function of the coupling device is to selectively engage the leader block, which is firmly attached to the end of the tape wound on the supply reel, in the generally rectangular tape cartridge.
The leader block interacts with the take-up reel such that the tape sees a smooth surface for storage on the take-up reel. The coupling device is generally designed so as to remain coupled to the leader block during the winding and unwinding operation and also to remain attached to the mechanism that has transported the leader block and the coupling device from the position adjacent to the cartridge to the position associated with the take-up reel.
As described in the copending applications, the coupling device includes a pin disposed with its axis parallel to the axis of rotation of the supply and take-up reels. The leader block must interact with the coupling device in a manner which permits the coupling device to be disposed coaxially with the axis of the take-up reel and in a manner such that the leader block is free to rotate about the pin during the winding and unwinding process.